Producing pavement bricks and sub base material in embankments from coal ash and slag masters thesis major sciences and management of the environment

THE JOINT ACADEMIC PROGRAM OF EXECUTIVE MASTER IN SCIENCES AND MANAGEMENT OF THE ENVIRONMENT BETWEEN INDUSTRIAL UNIVERSITY OF HOCHIMINH CITY AND LIÈGE UNIVERSITY PHAM THI TRUC THANH PRODUCING PAVEMENT BRICKS AND SUB-BASE MATERIAL IN EMBANKMENTS FROM COAL ASH AND SLAG A case study: VEDAN VIETNAM ENTERPRISE CORP., LTD Major: EXECUTIVE MASTER IN SCIENCES AND MANAGEMENT OF THE ENVIRONMENT MASTER’S THESIS HOCHIMINH CITY, YEAR 2018 The project was completed at The Industrial University of Ho Chi Minh City Supervisor’s name:……………………………………………………………… The thesis was taken at The Industrial University of Ho Chi Minh City date month year Committee members (name): …………………………………………………- Committee Chair ………………………………………………….- Commissioner ………………………………………………….- Secretary COMMITTEE CHAIR DEAN OF INSTITUTE OF ENVIRONMENTAL SCIENCE, ENGINEERING AND MANAGEMENT ACKNOWLEDGEMENTS First, I respectfully honor people who immensely supported and gave me assistance in this study: Prof Phd Nguyen Van Phuoc and Prof Angélique Léonard are my advisors, deepest gratitude for his invaluable assistance and support throughout my involvement in The Institute Of Science For Environmental Management, for his reviews, constructive advices and his patience and encouragement The Institute of Science for Environmental Management of Industrial University of Ho Chi Minh City who co-founded my studies at Industrial University of Ho Chi Minh City I would also like to thank my dear colleagues for their encouragement and helpful advices Many thanks to the people from Vedan Vietnam Enterprise Corp., Ltd Special thanks to my family and friends who always believe in me and be with me no matter where they are Author Pham Thi Truc Thanh ABSTRACT Environmental pollution resulted from coal based thermal power plants all over the world is cited to be one of the major sources of pollution affecting the general aesthetics of environment in terms of land use, health hazards and air, soil and water in particular and thus leads to environmental dangers Coal combustion residues (CCRs) is a collective term referring to the residues produced during the combustion of coal regardless of ultimate utilization or disposal It includes fly ash, bottom ash, boiler slag, and fluidised bed combustion ash and other solid fine particle According to Announcement No.279/TB-VPCP on Deputy Prime Minister Hoang Trung Hai's conclusions at the meeting on treating solutions as well as using ashes of thermal power plants Therefore, the study, processing and utilization of ash in the economic and technical fields should be paid special attention in the coming time Using pavement bricks, only sun-dried, not kiln-fired, are an indispensable trend in the world, bringing plenty of benefits compared to traditional bricks, although the production of modern technology, bricks will also consume large amounts of clay as well as burning plenty of fuel It is estimated that for the production of one trillion bricks, it would cost approximately 1.5 million m3 of clay and 150,000 tons of coal Use of ash as a construction material will utilize waste to recycle it into useful materials for the construction industry, replacing aggregate sand, cement with ash will reduce a quantum of raw materials used making blocks as well as leveling materials and saving production costs, saving land fund (used for burial of waste) During the operation of a coal-fired boiler with a capacity of 307 tons of steam per hour for 60 MW electricity generation, there were about 40 tons of fly ash per day, tons of coal slag per day and 1.5 tons of sludge / day In order to deal with this waste, Vedan desire to operate green technology to reuse fly ash and slag (coal combustion residues) which be made for pavement brick for the construction industry, saving land resources, and future potentials to achieve environmental sound management The research "Producing pavement bricks and sub-base material in embankments from coal ash and slag" was experimented with the purpose is reducing the volume of fly ash, coal slag and reduce green-house effect and global warming TABLE OF CONTENS TABLE OF CONTENS LIST OF TABLE LIST OF FIGURES INTRODUCTION 10 CHAPTER OVERVIEW OF RESEARCH ISSUES 16 1.1 Overview of coal ash and slag research 16 1.1.1 Domestic research 16 1.1.2 Research in the world 21 CHAPTER THE THEORY OF THE STUDY 25 2.1 Materials and methods of research 25 2.1.1 Quality input materials 25 2.1.2 Producing sub-base material in embankments from coal ash and slag 33 2.1.3 Producing pavement bricks from coal ash and slag 36 2.1.4 Experimental model 37 2.1.5 Method of research 38 CHAPTER RESEARCH RESULTS 39 3.1 Evaluation of performance results 39 3.1.1 Producing sub-base material in embankments from coal ash and slag 39 3.1.2 Producing pavement bricks from coal ash and slag 48 3.2 Discussion 54 CHAPTER CONCLUSION 57 LIST OF TABLE Table 0-1 Forecast of adobe brick demand for 2016-2021 12 Table 0-2 Capacity of adobe brick production in the provinces by 2020 13 Table 1-1 Demand for building materials baked and unbaked (billion standard bricks) 20 Table 2-1 Table quality analysis of slag/fly ash input 27 Table 2-2 Results of chemical analysis of coal slag 29 Table 2-3 Results of measurement of radioactive activity of fly ash and slag 32 Table 2-4 Mixing rate of ash with lime as leveling materials 33 Table 2-5 Mixing rate of pavement brick testing 36 Table 3-1 Results of particle composition after mixing 39 Table 3-2 Standard of elastic module for leveling materials 40 Table 3-3 Elastic module of coal slag materials after mixing 40 Table 3-4 Friction angle in of sample coal slag after mixing 43 Table 3-5 Volume compression coefficient of the sample coal ash after mixing 44 Table 3-6 Pre-consolidated stress 45 Table 3-7 Relationship between Natural weight and mechanical components and ingredients tested 46 Table 3-8 Resulting brick geometry after 28 days 49 Table 3-9 The result of the tiles compressive strength after 28 days 51 Table 3-10 Result of water ability of bricks after 28 days 53 LIST OF FIGURES Figure 1-1 Research products are applied from the project [6, 6] 18 Figure 1-2 Application of fly ash for pavement brick and breakwater, embankment 19 Figure 2-1 Fly ash sample 26 Figure 2-2 Coal slag sample 26 Figure 2-3 Process technology using waste as leveling materials 34 Figure 2-4 The process of trial production of pavement bricks 37 Figure 3-1 Sample VL1 - elastic module with horizontal pressure 25kPa, 50kPa, 75kPa 42 Figure 3-2 Sample VL2 - elastic module with horizontal pressure 25kPa, 50kPa, 75kPa 42 Figure 3-3 Sample VL3 - elastic module with horizontal pressure 25kPa, 50kPa, 75kPa 42 Figure 3-4 Standard Proctor Compaction Test 43 Figure 3-5 Compaction experiment – sample VL1 47 Figure 3-6 Compaction experiment – sample VL2 47 Figure 3-7 Compaction experiment – sample VL3 47 Figure 3-8 Brick samples tested after 28 days curing 49 Figure 3-9 This chart shows the compressive strength of pavement brick 52 Figure 3-10 This chart shows the water absorption of pavement brick 54 INTRODUCTION The reason for choosing the topic At present, Vietnam's economy is thriving strongly, along with the increasing number of production establishments, industrial parks This creates conditions to stimulate the production and business sectors to expand and develop rapidly However, this also generates a large number of waste including industrial and domestic solid waste, involving fly ash, bottom ash, boiler slag, and fluid bed combustion ash and other solid fine particles Typical is ash, slag from thermal power plants, boilers, according to the Ministry of Natural Resources and Environment, currently with 20 thermal power plants, slag generation of 15.8 million tons per year (2016) and up to 23 million tons / year (2020) equivalent to 63,000 tons / day Founded in 1991 in Phuoc Thai Commune, Long Thanh District, Dong Nai Province, Vedan Vietnam Joint Stock Company is a 100% foreign invested company with initial investment capital of USD 183 million After many years of escalating investment, expanding production and business, up to now, Vedan Vietnam JSC has raised the total investment capital of more than $ 500 million The company produces feed additives and some other products such as organic fertilizers, special chemicals, etc Paralleling the large productivity is the amount of solid waste generated from the kiln system Coal gas for generating electricity for the Company with coal slag of about tons / day, fly ash 40 tons / day and sludge about 1.5 tons / day With the purpose of recovering, treat and minimize impact on environment of coal wastes, pursuant to the Prime Minister's Decision No 789 / QD-TTG dated May 25, 2011 on Phung To approve the program on investment in solid waste treatment in the 2011-2020 period Of which, the 2016-2020 target must gather 90% of common 10 General comment on test results: All the test results of elastic module, compressibility, dry natural weight displayed that, with different mixing ratio have met the requirements of the material for road projects Sample VL3 are soaked in saturated humidity optimal and Maximum volume of dry volume reached the highest value compared to the corresponding values of the natural test sample VL1 mixed 5% lime of sample VL2 Therefore, escalating moisture content of VL3 to saturated moisture will strengthen the density when leveling the ground reduce the subsidence of the roadbed during use 3.1.2 Producing pavement bricks from coal ash and slag 3.1.2.1 Product quality in the production of fly ash pavement brick Concrete bricks are applied on pave pavements, streets, yards, squares Self-made concrete bricks must satisfy the technical conditions of QCVN 16: 2014 / BXD and TCVN 6476: 1999 - Self-made brick Technical requirements of indicators: - Size and size difference - Compressive strength - Waterproof ability - To take measurements after 28 days of curing NT1 NT2 48 NT3 NT4 NT5 NT6 Figure 3-8 Brick samples tested after 28 days curing 3.1.2.2 Size and size difference In the experimental study, five samples were taken for each of the measurements of geometry size over 28 days of curing (the results are attached to the appendix) Mean size was measured on 15 random capsules after curing period as follows: Table 3-8 Resulting brick geometry after 28 days Measurement results No Deviation allowed Length Width Height Length Width Height (mm) (mm) (mm) (mm) (mm) (mm) 221 109 62 ±2 NT1 222 109 60 49 ±2 ±3 Measurement results No NT2 NT3 Deviation allowed Length Width Height Length Width Height (mm) (mm) (mm) (mm) (mm) (mm) 221 109 60 221 109 61 211 109 60 220 109 59,5 222 109 60,5 220 110 62 220 110 60 220 110 62 221 110 60 221 109 58 220 109 60 220 110 61 221 109 59 221 110 59 221 109 59 221 110 59 221 110 59 Medium 219,2 109 60,6 ±2 ±2 ±3 Medium 220,4 109,6 60,8 ±2 ±2 ±3 Medium 220,6 109,4 59,6 ±2 ±2 ±3 NT5 Medium 221 50 109,8 59 Measurement results No Deviation allowed Length Width Height Length Width Height (mm) (mm) (mm) (mm) (mm) (mm) 221 110 59 221 109 60 ±2 NT6 220 110 59 221 109 60 221 109 58 109 ±3 Medium 220,8 221 ±2 109,2 59,2 59 (Source: Southern Institute of Building Materials, 2016) Note: TCVN 6476: 1999 - Self-made brick bricks General remarks: The resulting deviation is within the allowable range of TCVN 6476: 1999 3.1.2.3 Compressive strength The average compressive strength after 28 days curing time shown in the following table Table 3-9 The result of the tiles compressive strength after 28 days Compressive strength (MPa) Sample NT1 TCVN Brick Brick Brick Brick Brick No No No No No 21,9 21,63 25,81 26,9 19,15 51 6476:1999 Average 23,08 (M200) ≥20 Compressive strength (MPa) Sample TCVN 6476:1999 Brick Brick Brick Brick Brick No No No No No NT2 32,18 21,54 26,21 22,32 26,77 25,80 ≥20 NT3 25,08 21,56 20,09 12,5 14,47 18,74 ≥20 NT5 17,7 24,28 22,6 23,02 24,28 22,38 ≥20 NT6 10,9 12,81 11,66 12,46 12,54 12,07 ≥20 Average (M200) COMPRESSIVE STRENGTH (MPA) (Source: Southern Institute of Building Materials, 2016) Compressive strength (MPa) 30 20 20 20 10 23.08 25.8 20 20 18.74 22.38 NT3 SAMPLE BRICK NT5 20 12.07 NT1 NT2 Sample Brick NT6 TCVN 6476:1999 (M200) Figure 3-9 This chart shows the compressive strength of pavement brick Note: TCVN 6476: 1999 - Self-made brick General remarks: According to TCVN 6476:1999 Sample NT1, NT2 and NT5 the results are quite superb, reaching standard In which, sample NT2 has the highest compressive strength with mixing ratio fly ash (12,5%), sand (17,5%), coal slag (0%), cement 52 (10%) and stone (60%) Special, sample NT5 uses coal slag instead of sand and also produces quite good results up to 22.38MPa Sample NT3 is near the standard while sample NT6 is the lowest with mixing ratio fly ash (18%), sand (0%), coal slag (17,3%), cement (5%) and stone (60%) The reason why samples NT3 and NT6 are low is due to the cement composition with 5% 3.1.2.4 Water ability According to the results, the water ability of bricks after 28 days of curing time of brick samples is as follows: Table 3-10 Result of water ability of bricks after 28 days Water absorption (%) Sample TCVN 6476:1999 Brick Brick Brick Brick Brick No No No No No NT1 4,84 3,8 3,52 5,4 3,5 4,33 ≤10 NT2 4,13 4,77 4,71 5,1 4,56 4,32 ≤10 NT3 4,23 4,75 4,81 6,62 4,26 4,27 ≤10 NT5 4,24 4,75 4,32 5,24 4,65 4,01 ≤10 NT6 4,84 3,8 3,52 5,4 3,5 4,41 ≤10 Average (M200) (Source: Southern Institute of Building Materials, 2016) 53 Water Adsorption (%) 12 10 NT1 NT2 Sample brick NT3 Sample Brick NT5 NT6 TCVN 6476:1999 (M200) Figure 3-10 This chart shows the water absorption of pavement brick Note:QCVN16:2014/BXD-National Technical Regulation on products, construction materials - concrete tiles General remarks: The treatments were compared with TCVN 6476: 1999 (water anility of samples is less than 10%) 3.2 Discussion For the process “Producing sub-base material in embankments from coal ash and slag” The composition of the following particle sizes is mixed with the highest concentration in the range of 0.01-0.05 mm (from 50.5% to 52.8%) and the size range from 0.05 to 0.1 mm (17.3%) is equivalent to the size of dust - fine sand Through experimental methods such as elastic modulus test, load bearing capacity, compressibility calculation, sample density measurement, we can see that most materials are standard for the leveling process 54 With 95% mixture of fly ash, coal slag + 5% lime will achieve best performance And natural weight of the samples is approximately equal to natural weight of sand, so can use this mixture to subtitute sand as fill material Apparently, actual unit price of 1m3 of sand is estimated 300.000 VND, however cost of treating coal ash slag is roughly calculated only 270.000 VND/m3, less than ost of 1m3 of sand Therefore, the application of this technology will have undeniable effect on economic, 30.000 VND/m3 is saved on each blocks Utilizing a mixture of fly ash, slag - source local raw materials replacement sand will bring numberous benefits also overcome sand shortage in the area From the above conclusions, we can see the use of fly ash, coal slag for road pavement standard TCVN 6476: 1999 (M200) Water absorption of the samples is terific, samples are